The present invention relates to blow molded plastic containers in which food or food-related products, including cheese, may be stored.
The food industry initially utilized containers made from steel for holding and/or transporting food, especially for holding and/or transporting cheese. Increased weight, cost, the undesirable appearance of rust and other considerations have led many food manufacturers and transporters of food to switch from steel to plastic containers. Small plastic containers are typically injection molded, allowing for greater flexibility in the design and manufacture of the shapes and contours of the containers. Larger, industrial sized containers, on the other hand, are typically blow molded, which encumbers design flexibility. For example, sharp corners and other features may be designed and manufactured via injection molding with relatively few complications by, for example, the use of mold slides and other injection molding tools. The same design features, however, present greater challenges when manufacturing a larger, industrial sized container by blow molding. Thus, many features that would appear straightforward to use in smaller containers are often times deemed not feasible or altogether avoided in the manufacture of larger containers.
The containers must, nonetheless, meet several design criteria while still being hampered by blow molding manufacturing limitations. For example, the containers must be sufficiently durable to withstand forces during transport, such as the pressure from the food or food-related products pushing against the container walls and/or external forces from the containers bouncing or being pushed against a side of a transport vehicle. The containers must also properly store the food and still be sufficiently light for ease of handling.
To be easily stored, lids are removed from the containers, and the containers are nested within one another. But, the internal pressure from the food pushing outward against the container often causes the lower container portions and container bottoms to protrude outward and to permanently deform. The deformation makes it difficult and, in some cases, impossible to nest the containers within one another. Further, the containers must not buckle when subject to compressive forces.
In an attempt to prevent the lower container portions from deforming outwardly, some manufacturers implemented partial external ribbing that covered only about one-quarter of the lower container portion. The partial ribbing showed marginal, if any, benefits to prevent deformation—but the buckling problem and container floor deformation problems persisted.
In addition, because the containers are typically very heavy, especially when containing the food product, individuals typically tilt and roll the containers on a lower rim of the container. The lower rim used on many containers, however, is relatively feeble, having about the same thickness as the container wall. Because of the large forces borne by the lower rim, the lower rim often permanently deforms and, in extreme cases, fractures.
Some steel containers incorporate stacking beads to prevent a top container from sliding all the way within a bottom container in which the top container is nested. The stacking beads, however, are subject to large shear forces from the bottom containers pushing up on the stacking beads of the top containers. Specifically, the shear forces may cause the bead to bend upward or, in extreme cases, fracture. Further, when containers in the art are nested within one another, they often become wedged, making it difficult to densest (separate the containers from one another) the containers. Containers known in the art are also subject to other manufacturing and use problems.
Accordingly, there exists a need for an improved plastic, blow molded container that addresses the shortcomings of the containers now used in the art.